I/O Buffer Protection Circuit with Latch Register
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Solution Overview
Problem
Integrated circuits (ICs) face protection challenges when processing analog signals through I/O terminals, as abnormal conditions like overcurrent can lead to malfunction without effective protection mechanisms, making it difficult to detect and address such issues.
Innovation Solution
An input/output (I/O) buffer circuit is designed with a protection circuit that includes a register to latch logic signals during abnormal voltage levels, generating a logic control signal to deactivate the I/O unit and persisting this signal across power cycles, ensuring protection and detection of abnormal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the I/O unit processes analog signals through the I/O terminal, then the capability of the integrated circuit is enhanced, but the I/O terminal becomes vulnerable to abnormal conditions such as overcurrent and voltage level abnormalities
Solution Approach 1:
The protection circuit performs preliminary detection of voltage levels at the I/O terminal before abnormal conditions can cause damage. The circuit proactively monitors voltage levels and latches abnormal states using a register, enabling preventive protection rather than reactive response
Solution Approach 2:
The protection circuit acts as an intermediary between the I/O terminal and the I/O unit. It monitors the I/O terminal voltage levels and controls the I/O unit's operation through enable signals, preventing direct exposure to harmful voltage conditions while maintaining signal processing functionality
2Device complexity
If no protection circuit is implemented, then the device complexity is reduced, but abnormal conditions cannot be detected and the I/O unit cannot be protected
Solution Approach 1:
The protection circuit performs self-detection of abnormal conditions at the I/O terminal. The register automatically latches voltage level abnormalities without requiring external intervention, and the circuit self-controls the I/O unit through enable signals, providing autonomous protection functionality
Solution Approach 2:
The protection functionality is extracted as a separate, dedicated circuit module with its own register and control logic. This modular approach isolates the detection and protection functions from the main I/O unit, making the abnormal condition detection mechanism independent and specialized
3Reliability
If the I/O unit is deactivated to protect from abnormal conditions, then the I/O terminal is protected, but the I/O unit cannot perform its intended function during abnormal states
Solution Approach 1:
The enable signal controlling the I/O unit is dynamically adjusted based on real-time voltage level detection at the I/O terminal. The protection circuit transitions the I/O unit between active and deactivated states responsive to abnormal condition detection, optimizing the balance between protection and operational functionality
Data Source
AI summary
An input/output (I/O) buffer circuit includes an I/O unit and a protection circuit. The I/O unit selectively receives and outputs signals based on an enable signal. The protection circuit generates a logic control signal to deactivate the I/O unit in a state where a voltage level of the I/O terminal is abnormal. The protection circuit includes a register. The register latches a logic signal corresponding to the voltage level of the I/O terminal in a state where the voltage level of the I/O terminal is abnormal, outputs the logic control signal based on the logic signal, and is preset to output the logic control signal based on the logic signal when a power-off state resumes to a power-on state.